A magnetoresistance (MR) sensor is used in a read/write head to read magnetic fields on a recording medium of a magnetic storage device. An example is the read/write head of a computer hard disk drive or a magnetic recording tape drive. The read/write head is positioned closely adjacent to the recording medium, separated from the recording medium by an air bearing. A data bit is written onto an area, usually a track, of the recording medium using the writing portion of the read/write head by locally changing its magnetic state. That magnetic state is later sensed by the MR sensor to read the data bit.
A continuing trend is to decrease the size of the sensing area of the MR sensor, which permits an associated decrease in the track width on the magnetic recording medium. As a result, the number of tracks and the density of data storage on the recording medium are increased. As the size of the sensing area is reduced, the fabrication of the small-scale structures to have the required spatial sizes and sharp edge definitions becomes more difficult. These difficulties are related in part to the physical limits of photolithography and other techniques used in the fabrication processes. In some parts of the fabrication processing, the limits are being reached so that further decreases in the size of the feature result in a loss of edge definition that adversely affects the magnetic sensing functionality.
There is a need for an improved approach to the fabrication of fine features in MR sensors and other structures. The present invention fulfills this need, and further provides related advantages.